<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    .circle{
      width: 100px;
      height: 100px;
      border-radius: 50%;
      background: green;
    }
    .eclipse{
      width: 200px;
      height: 100px;
      border-radius: 50%;
      background: green;
    }
    .other{
      width: 200px;
      height: 100px;
      border-radius: 50px;
      background: green;
    }
    .half-eclipse{
      width: 200px;
      height: 50px;
      border-radius: 50% / 100% 100% 0 0;
      background: green;
    }
    .half-eclipse2{
      width: 100px;
      height: 100px;
      border-radius: 100% 0 0 100% / 50%;
      background: green;
    }
    .quarter-eclipse{
      width: 100px;
      height: 50px;
      border-radius: 100% 0 0 0;
      background: green;
    }
  </style>
</head>
<body>
  <div class="circle"></div>
  <div class="eclipse"></div>
  <div class="other"></div>
  <div class="half-eclipse"></div>
  <div class="half-eclipse2"></div>
  <div class="quarter-eclipse"></div>
</body>
</html>
